Autodesk SketchBook Mobile is a professional-grade paint and drawing application designed for the iPhone and iPod Touch. SketchBook Mobile offers a full set of sketching tools and delivers them through a streamlined and intuitive user interface. Use it to digitally capture your ideas as napkin sketches or produce artwork on-the-go. With the same paint engine as the renowned SketchBook Pro software, SketchBook Mobile delivers sophisticated brushes and fluid pencils.
This is a terrific app and it is curently available for only $0.99/£0.69 instead of $1.99/£1.49 – you can download it here.